You can use certain private delivery services designated by the IRS to meet the “timely mailing as timely filing/paying” rule for tax returns and payments. These private delivery services include only the following.

• United Parcel Service (UPS): UPS Next Day Air, UPS Next Day Air Saver, UPS 2nd Day Air, UPS 2nd Day Air A.M., UPS Worldwide Express Plus, and UPS Worldwide Express.

The private delivery service can tell you how to get written proof of the mailing date.

Why would it recommend a bunch of overnight, next-day, and 2nd-day services if the April 15th deadline is for postmarking? That suggests that the April 15th deadline is actually when it needs to be received by the IRS.

It doesn't even mention the U.S. Postal Service.

So does Form 4868 need to be postmarked by April 15 or received by the IRS by April 15?

3 Answers
3

If you send it by USPS (first class or better), the deadline is "postmark by April 15".

If you send it by one of the specific UPS or FedEx services listed, the deadline is also "postmark by April 15".

If you send it by any other service, the deadline is "received by April 15". At one time this was the rule for every service except USPS, so the USPS/FedEx services listed have been granted an exception.

I assume the reason that only 1-2 day services have this exception is because the IRS wants to get the form within a few days after April 15. They trust the USPS to achieve that, and they also trust the 1-2 day services listed, but they wouldn't trust some hypothetical UPS Super-Slow Class service, nor Joe's Carrier Pigeon Delivery Service.

In general, USPS is likely to be your best bet, since it qualifies for the postmark deadline ("timely mailing") and is probably cheaper than other options.

U.S. Postal Service is not a private delivery service. You can most definitely use USPS, and the proof of mailing with USPS is obtained when you request certificate of mailing (i.e.: send what is called "a certified" letter).

The requirement is to mail by April 15th. It doesn't have to be received by the IRS by that time.

A small correction: "Certificate of mailing" and "certified mail" are two distinct USPS services with similar names. The former only provides proof that you mailed the letter. The latter also provides proof that it was delivered, and optionally can include a "return receipt" sent back to you with the recipient's signature. See usps.com/ship/insurance-extra-services.htm?
– Nate EldredgeApr 10 '15 at 15:54

Always get a return receipt when mailing your tax return. If you get a late filing or late payment penalty by mistake, you will need the receipt for your defense.
– FirejavaApr 10 '15 at 16:12